Kriging-based model for CPTu data management in conductor casing design

Abstract

In oil and gas industry, conductor casing design and installation provide structural integrity to the well system, withstanding loads from equipment and offshore environment during all construction and production phases. In this context, decision-making process of a suitable soil-casing coupling must be supported by high-quality soil data. As such, evaluation of the soil spatial variability demands several assessments of the soil properties in different locations and, in ultradeep waters, execution of a reasonable number of experimental measurements is cumbersome and expensive. Regarding the aspect of parametric modeling using limited information, the current work presents an approach for managing CPTu data to bridge geotechnical and top hole design knowledge using geostatistical methods and recommended practices for oil and gas industry. This approach integrates kriging-based techniques and DNV formulation in an integrated model to analyze geotechnical parameters depth- and geographically-wise. All evaluated information is used to complement experimental analysis, providing indicators of geomechanical behavior within highly correlated area. The developed methodology is made available in a prototype which allows handling CPTu parameters in a user-friendly automated way.